Outbreaks Linked to Drinking Water Mainly Due to Legionella

Updated: Nov 14th 2017

TUESDAY, Nov. 14, 2017 (HealthDay News) -- Most drinking water-associated waterborne disease outbreaks and waterborne disease outbreaks associated with environmental or undetermined exposure to water are due to Legionella, according to two studies published online Nov. 9 in Morbidity and Mortality Weekly Report.

Katharine M. Benedict, D.V.M., Ph.D., from the U.S. Centers for Disease Control and Prevention, and colleagues analyzed outbreaks reported to the CDC Waterborne Disease and Outbreak Surveillance System as of Dec. 31, 2015. The researchers found that 42 drinking water-associated outbreaks were reported during 2013-2014, accounting for at least 1,006 cases of illness, 124 hospitalizations, and 13 deaths. Fifty-seven percent of these outbreaks and all the deaths were associated with Legionella. Sixty-nine percent of the reported illnesses occurred during four outbreaks, which involved a chemical or toxin and the parasite Cryptosporidium.

R. Paul McClung, M.D., from the CDC, and colleagues examined waterborne disease outbreaks in the United States caused by environmental exposure to water or an undetermined exposure to water. The researchers found that 15 outbreaks associated with an environmental exposure to water and 12 outbreaks associated with an undetermined exposure to water were reported during 2013-2014; these resulted in at least 289 cases of illness, 108 hospitalizations, and 17 deaths. Sixty-three percent of the outbreaks, 94 percent of hospitalizations, and all deaths were due to Legionella.

"Water management programs can effectively prevent outbreaks caused by environmental exposure to water from human-made water systems, while proper point-of-use treatment of water can prevent outbreaks caused by ingestion of water from natural water systems," McClung and colleagues write.